This invention generally relates to automatic key duplication, and more particularly a device to help automatically determine key cut attributes.
In the key making art, each lock manufacturer has adopted a number of different key blanks, each with its own unique shape and specific groove characteristics. Further, for each key blank, the manufacturer has assigned one or more known key cut codes that define the manner in which the key blank can be cut to match the manufacturer""s lock.
Once a locksmith determines which key blank it is among the thousands made, he must be skilled at tracing or cutting the notches, cuts or bits of the object key into the correctly identified key blank. If the key cuts are not traced precisely, then the new key will not work in the lock.
The manufacturer""s key cut codes define the relationship between the cuts and key blank, and between one cut and other. The following characteristics or attributes are representative:
1) the distance from the key shoulder to the center of the first cut;
2) the distance between cuts, distance being measured from the center of one cut to the center of an adjacent cut;
3) the depth of each cut;
4) the angle of each cut;
5) the length of the flat at the bottom of each cut;
6) the distance between the tip and key shoulder.
Once such attributes of an object key can be extracted, recognized, and compared to that which was supplied by an original key manufacturer, and after the appropriate key blank is selected, a new key duplicating the original can be selected and cut.
Various types of key making machines currently exist which identify and utilize a key manufacturer""s coding to duplicate a customer""s key. However, none of the following patents teaches a method or apparatus that helps to extract object key information absent some means of making physical referential contact with the object key.
U.S. Pat. No. 2,070,228, issued in 1935, is a seminal patent relating to key cut codes. The device disclosed measures relative depth of key cuts using spring-loaded tumblers that make physical contact with key cuts. Analysis of the slope of the key cut is not considered, though. The acquired data is then used by a locksmith to determine an appropriate key code.
U.S. Pat. No. 4,090,303, relating to a key decoding apparatus, discloses a method of determining the original key cuts utilizing manufacturer""s predetermined key cut depth and spacing. The key decoding apparatus disclosed employs an index card having sequential indexes thereon corresponding to a predetermined coded depth of the key desired to be duplicated. This card is inserted into a housing and the key to be duplicated is inserted into a slot in the housing where it engages an indexing member which enters one of the key cuts on the key and indicates on the card the coded depth of the key cut. The angle of the cut of the same key cut may also be determined. The remaining key cuts of the key may be decoded in like manner.
U.S. Pat. No. 3,796,130 issued in 1974 to Garner discloses a semiautomatic key duplicating and vending machine. This device requires the customer to place his key into one of a plurality of slots, each slot adapted to receive a key blade of a different cross-section corresponding to the shape of one of the blanks in storage. Selection of the proper slots provides a means for selecting the appropriate key blank in storage and automatically positions such blank for trace cutting a duplicate profile to that of the customer""s key. The principal disadvantages of such a device are that smaller keys fit into larger holes, its inability to determine the differences in key blade length or shoulder position which can distinguish one key blank from another, and the fact that this device merely duplicates the cut features of the customer""s key which may be overly worn.
U.S. Pat. No. 4,717,294 discloses a key cutting device, which cuts key blanks by employing a set of coded depth keys supplied by the lock manufacturer.
U.S. Pat. No. 4,899,391 discloses a system for identifying an appropriate key blank from a pattern comprised of a plurality of horizontal grooves of a predetermined depth and spacing taken from the image of the front profile of the key. The principal disadvantage of such a device is that it cannot measure depths of cuts and so cannot decode the characteristics of the key cuts.
U.S. Pat. No. 3,442,174 issued to Weiner et al. for a key blank dispensing and cutting apparatus that requires the assistance of the customer in selecting a slot in which to insert the blade of the key. Once having found the slot, the blank identification process is completed. Unfortunately, the apparatus only allows for identification of the profile of the key and does not take into account keys having identical profiles and varying lengths and shoulder positions and smaller keys that fit into larger holes. Moreover, the apparatus is limited to forty-eight known key blanks. Additionally, the selection method disclosed reveals mechanical push rods, one for each of forth-eight key blanks to push a key blank out of its respective key.
Other representative art includes U.S. Pat. No. 5,245,329, 5,050,462; 4,929,129; and 3,358,561.
These above methods and apparatus for automatic key making require skill on the part of the operator to fixture the object key in some fashion.
While unrelated to the key making, art, the following patents are nevertheless of note. U.S. Pat. No. 4,809,341 teaches a method and apparatus used in semiconductor device fabrication for a reticule or mask image, which has a slight modification of reduction or magnification, using a comparison method in which the real image pattern is compared with the pattern produced from design data. U.S. Pat. No. 4,805,224 reveals a pattern recognition method and device employing second order differential analysis of distinctive features. Other art referenced includes U.S. Pat. No. 4,143,582; 4,324,513; 5,120,010; 5,103,120; 4,899,391; and 3,796,130.
U.S. Pat. No. 5,807,042 discloses a system for automatically extracting attribute information by automatically reading an object key and comparing the attributes of the object key with a master pattern memory of known manufacturers"" keys. Then it selects the proper matching key blank and cuts it to the original key cut codes established by the manufacturer. Alternatively, the key blank can be trace-cut, duplicating the used attributes of the object key. Alternatively, key cuts hybridizing the key cut features of the object key and key cut codes of a known manufacturer""s key may be determined for use with the corresponding key blank. For decoding depth of key cuts this invention may comprise a transparent section on which an object key may be supported which is rotated and a back lighting means is used to pass light through the transparent section and project an image of the object key. From the image received, the position of the longitudinal centerline of the object key relative to a fixed datum is determined and an output signal generated. The object key may then be rotated to align it. Object key attributes may thus be extracted without fixturing or confining the object key in a holder or like device and a correct key blank may be identified.
This system consists of many sensitive mechanical, electrical and rotating, moving optical devices, and as the result will likely be unreliable and inaccurate. This system is also very sensitive to vibration and cannot be made portable, so it cannot be useful in the field, and will need constant adjusting and maintenance by a highly educated specialist.
A primary advantage of the present invention is to provide an apparatus to help in determining key cut information without having to physically engage each key cut.
Another advantage of the present invention is to provide a device that uniformly, and without skilled intervention, positions a variety of keys for helping to extract key cut information.
In accordance with a preferred embodiment of the present invention, a device to help determine key cut attributes comprises a holding device to uniformly hold an object key, a luminescent device on one side of the held object key and a device on the other side of the object key to store an image of the object key created by the outline created by the luminescent device.
In accordance with another preferred embodiment of the present invention a device for helping to extract key cut information comprises a key holder to position a key vertically between a luminescent light strip and motionless camera to create an outline of the key cuts for storage in a computing device.
Other objects and advantages of the cutting-device will become apparent from the following descriptions, taken in connection with the accompanying drawings, wherein, by way of illustration and example, an embodiment of the present invention is disclosed.